Ball and socket swivel for an electric light receptacle



R. A. MULAC Oct. 27, 1959 BALL AND SOCKET SWIVEL FOR AN ELECTRIC LIGHTRECEP'I'ACLE Filed Dec. 6, 1957 United States Patent BALL AND SOCKETSWIVEL FOR AN ELECTRIC LIGHT RECEPTACLE Rudolph A. Mula'c, Chicago, Ill.

Application December 6, 1957, Serial No. 701,003

4 Claims. (Cl. 285-91) be interposed between an electric lightreceptacle and the support for the receptacle, and which will allowuniversal swiveling of the electric light receptacle without exposingany electrical wires at or around the swivel joint.

It is a further object of the present invention to provide a swiveljoint of the above mentioned character wherein the wires for carryingelectric connections to the light bulb receptacle extend lengthwisethrough the ball and socket connection.

It is a still further object of the present invention to provide a balland socket mechanism of the above mentioned character that provides ascrew threaded mount for receiving an electric light bulb receptacle andwhich is also screw threaded to provide for mounting for the ball andsocket mechanism on a lamp support in such manner as to permit universalswiveling of the electric light bulb receptacle and which will alsopermit screwing or unscrewing of the electric light bulb receptacle onto or off of the ball and socket mechanism without requiring any specialtools or the like for holding the ball and socket mechanism in position.

The attainment of the above and further objects of the present inventionwill be apparent from the following specification taken in conjunctionwith the accompanying drawings forming a part thereof.

In the drawing:

Figure 1 is a longitudinal view, in partial section, showing themechanism of the present invention as applied between an electric lightbulb receptacle and a conventional support therefor;

Figure 2 is a top plan view of the ball and socket mechanism;

Figure 3 is a longitudinal sectional view taken along the line 33 ofFigure 2;

Figure 4 is a longitudinal sectional view taken along the line 44 ofFigure 2 and looking in the direction of the arrows; and

Figure 5 is a sectional view taken along the line 5--5 of Figure 4.

Like figures designate like parts throughout the different figures ofthe drawing.

In Fig. 1 there is shown in a fragmentary manner an incandescentelectric light bulb 1 having a male screw type base adapted to bethreaded into a conventional electric light bulb receptacle 3 which mayor may not have a switch 4 and which terminates in a female threadedneck 6 that is adapted to be threaded on to the top of a threaded typesupport 8, and is to be locked in place as by a screw 9.

The electric wires for establishing the connections within thereceptacle extend into the receptacle through the support 8 and neck 6.In the present instance, a ball and socket mechanism 10 of the presentinvention is interposed between the support 8 andthe neck 6.

The ball and socket mechanism includes a ball part 12 which in thisinstance is the upper part, and a socket forming part 14 which in thisinstance is the lower part.

The ball forming part 12 has an externally threaded neck 15 thatterminates in an inverted fruszto-conical base 16 which in turnterminates in a ball or spherical part 18. A longitudinal bore 20extends through the bore part 12 concentric with the axis of the threadson the neck 11.5. In the periphery of the ball part 18 there is formed agroove 22 substantially V-shaped that extends along an arc which is agreat circle of the sphere or ball part 18, said great circle beingcentered in a plane that includes the longitudinal axis of the bore 20.The groove 22 is of a length approximately degrees along the peripheryof the ball 13, although the extent of this are may .be greater or lessthan 90 degrees depending upon the amount of tilting that is to bepermitted to the axis of the neck 20.

The socket part 14 of the ball and socket mechanism consists of a loweror base portion 25 that is internally threaded at its bottom at 26. Thepitch of the threads 26 is the same as the threads 15 which is the sameas the pitch of the threads at the top of the support 8. As a result ofthis arrangement the threads 26 may be threaded on to the support 8 formounting the ball and socket mechanism, and the neck 6 of the electriclight receptacle 3 may be threaded on the threads 15 for mounting theelectric light receptacle. The base portion 25 has a longitudinal bore27 therethrough through which are passed the electrical conductors forthe electric light bulb, and has at the top thereof a counter bore 23that provides a peripheral shoulder 29 that constitutes a seat for aspring 301. A ring 32 is located within the counter bore 23 andconstantly pressed upwardly by the spring 30, the ring 32 being curvedon the inside to coincide with the surface of the ball 18 so that theball 18 is free to slide along the inner surface of the ring 32. The topof the base 25 is externally threaded as indicated at 33, to receive afemale threaded cap 34 which in Figures 3 and 4, is in invertedposition. The top end 35 of the cap 34 has an opening that seats on theball 18, said opening being of a diameter less than the diameter of theball 18 and greater than the maximum diameter of the frustoconical base16, so that the neck 15 and base 16 of the ball part 12 may be insertedthrough the central opening in the top end 35 of the cap 34, the upwardmovement thereof being limited by the ball 18.

When the cap 34- is screwed into position so that the bottom of the caprests on the external peripheral shoulder 33 of the base 25, there is anannular space 38 between the underside of the cap 34 and the top of thebase 25. This space constitutes a raceway for a ball bearing 4% thatalso extends into the groove 22 and is confined between the groove 22and the groove or annular space 38. The difference between the outsidediameter of the ball 18 and the inside diameter of the cap 34 at theannular space 38 is less than the diameter of the ball bearing 40.

After assembly of the parts thus far described, the cap 35 is drilled toform a hole 44. This hole extends through the top 35 of the cap 34 andthrough the threads between the cap 34 and the base 25. After this holeis formed, a pin 45 is driven into this hole until the top of the pin isflush with the outside surface of the top 35.

The pin 45 serves a number of purposes. First it looks the cap 35 on tothe base 25 by effectively preventing turning of the cap on the base. Inaddition, this pin extends through the annular space 38 and where thepin is located and constitutes a restriction in radial extent of theannular space and limits the movement of the ball bearing 40 in theraceway 38. If an attempt is made to turn the ball part 12 in eitherdirection as indicated by the arrows 47 in Figure 5, the permissibleturning is limited to an amount slightly less than 360 degrees from thedotted line position illustrated in Figure 5.

The spring 30 constantly urges the ring 32 and with it the ball 18, inan upward direction and thus creates a pressure engagement between theball 18 and the bore in the top 35 through Which the ball extends. Thispressure engagement creates enough friction between the members so thatthe ball 18 remains in any position to which it has been moved, whilepermitting adjustment of the ball against the frictional resistance.

The electric wires for extending the electric connections to the lightbulb receptacle 3 are indicated at 50. Those wires extend through thesupport 8 and through the bore 27 in the base 25, thence through thebore 20 in the ball part 12 and through the neck 6 and into thereceptacle. The receptacle may be locked against turning in the usualmanner as by providing a flat 52. on the outside of the neck 15 whichflat receives the end of the screw 9.

From the above description it is clear that the provision of the pin 45which passes through the annular space 38 limits the rotation of theball member in a direction axially of the neck 15 and thus permitsunthreading of the electric bulb light receptacle when that isnecessary, of course the screw 9 being first loosened.

In compliance with the requirements of the patent statutes, I have hereshown and described a preferred embodiment of the present invention. Itis, however, to be understood that the invention is not limited to theprecise construction here shown, the same being merely illustrative ofthe principles of the invention.

What I consider new and desire to secure by Letters Patent is:

1. A ball and socket mechanism for an electric light receptacle, saidmechanism being threaded at one end for threaded engagement with theneck of the receptacle and having a ball and socket connection betweenits two ends and a continuous bore therethrough from end to end for thepassage of electrical conductors therethrough, the mechanism including aball part and a socket part, the two parts having universal angularadjustment with respect to one another, yielding means maintaining thetwo in frictional pressure engagement whereby the two are held byfriction in their adjusted positions, the ball part having a grooveformed in its outer surface and the socket part having a groove formedin a surface thereof opposite the ball surface, the two grooves crossingone another, a ball bearing in both of the grooves at the crossing, oneof the grooves extending through an arc of 360 degrees, and a pinextending across and intersecting the one groove and constituting a stopfor the ball whereby abutment of the ball bearing with the pin limitsthe turning of the ball and socket joint about the center axis of saidone groove to an amount less than 360 degrees, the socket partcomprising two threadingly engaged pieces adapted to receive the ballend between them, said pin also extending through the two pieces of thesocket part and holding them against separation.

2. A ball and socket mechanism for an electric light receptacle, saidmechanism being threaded at one end for threaded engagement with theneck of the receptacle and having a ball and socket connection betweenits two ends and a continuous bore therethrough from end to end for thepassage of electrical conductors therethrough, the mechanism including aball part and a socket part, the two parts having universal angularadjustment with respect to one another, yielding means maintaining thetwo in frictional pressure engagement whereby the two are held byfriction in their adjusted positions, the ball part having a grooveformed in its outer surface and the socket part having a groove formedin a surface thereof opposite the ball surface, the two grooves crossingone another, a ball bearing in both of the grooves at the crossing, oneof the grooves extending through an arc of 360 degrees, and a pinextending across and intersecting the one groove and constituting a stopfor the ball whereby abutment of the ball bearing with the pin limitsthe turning of the ball and socket joint about the center axis of saidone groove to an amount less than 360 degrees 3. A ball and socketmechanism comprising a ball part and a socket part, said two partshaving universal angular adjustment with respect tozo-rie another,yielding means maintaining the two parts in frictional pressureengagement whereby the two are held by friction in their adjustedpositions, the ball part having a groove formed in its outer surface andthe socket part having a groove in a surface opposite the ball surface,the two grooves crossing one another, a ball bearing in both of saidgrooves at the crossing, said ball part being rotatable about the centeraxis of the groove in said socket part, and stopforming means located inthe groove in said socket whereby abutment of the ball bearing with saidmeans limits the rotation of the ball part about said center axis.

4. A ball and socket mechanism for an electric light receptacle, saidmechanism being threaded at one end for threaded engagement with theneck of the receptacle and having a ball and socket connection betweenits two ends and a continuous bore therethrough from end to end for thepassage of electrical conductors therethrough, the mechanism including aball part and a socket part, the two parts having universal angularadjustment with respect to one another, yielding means maintaining thetwo in frictional pressure engagement whereby the two are held byfriction in their adjusted positions, the ball part having a grooveformed in its outer surface and the socket part having a groove formedin a surface thereof opposite the ball surface, the two grooves crossingone another, a ball bearing in both of the grooves at the crossing, oneof the grooves extending through an arc of 360 degrees, and means in theone groove and constituting a stop for the ball whereby abutment of theball bearing thereagainst limits the turning of the ball and socketjoint about the center axis of said one grove.

References Cited in the file of this patent UNITED STATES PATENTS1,166,752 Finizio Jan. 4, 1916 1,697,037 Witz Jan. 1, 1929 1,927,703Glowacki Sept. 19, 1933 2,334,436 Pcrbal Nov. 16, 1943

